Just picked up my new 2500 HD with the 325 HP engine and automattic. Its my first diesel and I am thrilled with its inital performance. Great acceleration, smooth running and very quiet. I have no experience with a jake brake. I am also a loss to fully understand what effect adding one has on the WARRANTY. Any help on that score would be appreciated. I would also like to hear about favorite brands of brakes. Thanks for any replies. MIKE